Aerating with olive oil?

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It does seem to work. I have used it off and on to supplement manual aeration, but right now I have an IPA in the fermentor that uses just olive oil; no manual aeration whatsoever. I am very interested to see how it'll turn out! If it works well, I plan on switching to it permanently.
 
Its been discussed (try a search)....there are some significant flaws in the work, but then you also have a bunch of ancedotal evidence from homebrewers (such as ArcaneXor) who say its for real.

If you look at the thesis in the link you posted, the big flaw (at least that I saw) is that they don't have a control sample that was not aerated at all to compare to the samples oxygenated by either stone or by olive oil. Their rationale for this was that if olive oil did not have an effect on fermentation, then you would expect to see a decrease in yeast/fermentation measures. In other words, a lack of a response is their evidence that it olive oil works.

Sure enough, their data shows is no difference between oxygenation with a stone and olive oil addition, which they interpret to mean that olive oil is just as effective as an oxygen stone in promoting yeast growth and fermentation.

What this experiment assumes is that oxygenation is an effective promoter of yeast growth/fermentation in the first place! However, It is is entirely possible that oxygenation (by whatever means) it has no effect in this scenario, right? Therefore, you can really say conclusively that olive oil is good at oxygenating wort as measured by fermentation output, when its unclear if oxygenation (by whatever means) is good at stimulating fermentation. This is where the no-oxygenation control comes in....to first show that you need good oxygenation...and then you can conclusively say if olive oil is any better/worse than the stone at oxygenating wort.


PS...before people start throwing more anecdotal data my way, I have some of my own: This study was fermenting a 1.057 wort and testing oxygenation with either a stone or olive oil. I've fermented many of 1.057-60 wort without any oxygenation and they've all fully attenuated and fermented cleanly. This (albeit anecdotal!) evidence suggests that you don't need to oxygenate 1.057 wort for adequate fermentation.
 
I've heard of this as well, but I heard the amount of olive oil you'd need for a homebrew batch is like less than 1 drop. I'm a little skeptical...so please report back with your results! How much oil did you add?
 
anyone ever go with no aeration? just curious because water already has oxygen in it right? (not just the H2O part i mean extra) not sure what happens when you boil it though. seems like if you just shake it up the bubbles come out of solution pretty quick anyway.
 
rycov said:
anyone ever go with no aeration? just curious because water already has oxygen in it right? (not just the H2O part i mean extra) not sure what happens when you boil it though. seems like if you just shake it up the bubbles come out of solution pretty quick anyway.
Click to expand...

Boiling causes the oxygen to come out of solution, which is the rationale for oxygenation/aeration. You need some oxygen in solution for proper yeast cell membrane growth...or so the theory goes...
 
Yes but it only works on Italian beers.

Olive Oil is touted as being the highest in Linoleic Acid next to just straight Linoleic Acid.
 
broadbill said:
Its been discussed (try a search)....there are some significant flaws in the work, but then you also have a bunch of ancedotal evidence from homebrewers (such as ArcaneXor) who say its for real.

If you look at the thesis in the link you posted, the big flaw (at least that I saw) is that they don't have a control sample that was not aerated at all to compare to the samples oxygenated by either stone or by olive oil. Their rationale for this was that if olive oil did not have an effect on fermentation, then you would expect to see a decrease in yeast/fermentation measures. In other words, a lack of a response is their evidence that it olive oil works.

Sure enough, their data shows is no difference between oxygenation with a stone and olive oil addition, which they interpret to mean that olive oil is just as effective as an oxygen stone in promoting yeast growth and fermentation.

What this experiment assumes is that oxygenation is an effective promoter of yeast growth/fermentation in the first place! However, It is is entirely possible that oxygenation (by whatever means) it has no effect in this scenario, right? Therefore, you can really say conclusively that olive oil is good at oxygenating wort as measured by fermentation output, when its unclear if oxygenation (by whatever means) is good at stimulating fermentation. This is where the no-oxygenation control comes in....to first show that you need good oxygenation...and then you can conclusively say if olive oil is any better/worse than the stone at oxygenating wort.


PS...before people start throwing more anecdotal data my way, I have some of my own: This study was fermenting a 1.057 wort and testing oxygenation with either a stone or olive oil. I've fermented many of 1.057-60 wort without any oxygenation and they've all fully attenuated and fermented cleanly. This (albeit anecdotal!) evidence suggests that you don't need to oxygenate 1.057 wort for adequate fermentation.
Click to expand...

You are too hung up on terminal gravity as the metric of success. We aren't making industrial ethanol here. That aeration affects the flavor of beer is heavily tested and known and the New Belgium experiment shows that olive oil and aeration produce different flavor profiles as confirmed by gas chromatograph and tasting panel.
 
I almost never aerate or oxygenate my wort before pitching yeast. I always use a stirplate starter of the correct size recommended by MrMalty. It's my understanding that Oxygen is required for the growth phase of the yeast which has already been accomplished by the stirplate.

The only beer that has had an attenuation problem was a large belgian quad that I underpitched.

-chuck
 
GaryJohn said:
I've heard of this as well, but I heard the amount of olive oil you'd need for a homebrew batch is like less than 1 drop. I'm a little skeptical...so please report back with your results! How much oil did you add?
Click to expand...

The New Belgium study used 4 different amounts, you can read it in there.

The amount for 5 gallons would be challenging to measure. I would personally make an olive oil water emulsion (but what emulsifying agent to use? lecithin? maybe star san?) with whatever amount of oil I could measure with a reasonably priced pipette and then add a small amount of the emulsion.
 
remilard said:
You are too hung up on terminal gravity as the metric of success. We aren't making industrial ethanol here. That aeration affects the flavor of beer is heavily tested and known and the New Belgium experiment shows that olive oil and aeration produce different flavor profiles as confirmed by gas chromatograph and tasting panel.
Click to expand...

Actually, I'm more hung up on the design of the experiment, and if oxygenation is even required in the first place. I was using terminal gravity/FG to illustrate my criticism, but it holds true for all of the other metrics and were not different between olive oil and traditional aeration.

As for the different ester profile: Differences were only detected in the super-sensitive GC experiments and not in the sensory panels. How significant are those differences in ester profiles then?
 
broadbill said:
Actually, I'm more hung up on the design of the experiment, and if oxygenation is even required in the first place. I was using terminal gravity/FG to illustrate my criticism, but it holds true for all of the other metrics and were not different between olive oil and traditional aeration.

As for the different ester profile: Differences were only detected in the super-sensitive GC experiments and not in the sensory panels. How significant are those differences in ester profiles then?
Click to expand...

Read the study more carefully, the tasting panel reported the increased esters in all 4 tests.

As for whether or not oxygen at the onset of fermentation affects beer flavor I don't know what to tell you other than that there is a mountain of literature that you are apparently intentionally ignoring.
 
I saw the same issue Bill mentioned in the study. But it is widely accepted that wort needs aeration in order for healthy yeast to bud and propagate. There are a multitude of factors that goes into healthy yeast and fermentation. Also, the levels of various nutrients in the wort, temperature and even the strain of yeast being used.

A basic way of testing this at home is simple. Brew a 5 gallon batch of beer. Split the wort into 5 1 gallon fermenters (same style) and using the same pack of yeast, pitch the yeast (hard part, ensuring each batch has the same quantity of yeast to start) and place into a controlled temp fermentation chamber. In 1 use olive oil, in the other aerate with oxygen and an aeration stone, in another aearate by shaking/stirring, in another no aeration and the final one use straight lineolic acid. Ensure each batch has the same starting SG before pitching. Then each day measure the SG of each batch. Then graph it out.

This is by no means a hard and fast study as there will be issues, but it can give you a ballpark idea of the different methods. And at the end of the experiment, combine all 5 batches into a keg, carb it and then drink the experiment.
 
amrmedic said:
I saw the same issue Bill mentioned in the study. But it is widely accepted that wort needs aeration in order for healthy yeast to bud and propagate. There are a multitude of factors that goes into healthy yeast and fermentation. Also, the levels of various nutrients in the wort, temperature and even the strain of yeast being used.

A basic way of testing this at home is simple. Brew a 5 gallon batch of beer. Split the wort into 5 1 gallon fermenters (same style) and using the same pack of yeast, pitch the yeast (hard part, ensuring each batch has the same quantity of yeast to start) and place into a controlled temp fermentation chamber. In 1 use olive oil, in the other aerate with oxygen and an aeration stone, in another aearate by shaking/stirring, in another no aeration and the final one use straight lineolic acid. Ensure each batch has the same starting SG before pitching. Then each day measure the SG of each batch. Then graph it out.

This is by no means a hard and fast study as there will be issues, but it can give you a ballpark idea of the different methods. And at the end of the experiment, combine all 5 batches into a keg, carb it and then drink the experiment.
Click to expand...

I would hope that anybody criticizing the methods used to produce the paper in the OP would not seriously propose that a casual test with no trained tasting panel and statistical analysis is acceptable.
 
remilard said:
Read the study more carefully, the tasting panel reported the increased esters in all 4 tests.

As for whether or not oxygen at the onset of fermentation affects beer flavor I don't know what to tell you other than that there is a mountain of literature that you are apparently intentionally ignoring.
Click to expand...


I did read it and I'll rephrase...the sensory panel could not consistently taste flavor difference in between the two samples.

The results are all over the place:

In trial 1: GC showed significantly different levels of isolamyl acetate and ethyl hexanoate, yet there no significant differences in the sensory panel for these compounds. Just that they could "taste differences" in ester and they preferred the olive oil treated beer.

In trial 2: GC showed that levels of ethyl hexoanoate were not significantly different, yet the sensory panel was somehow able to pick up a significantly different level of ethyl hexoanoate??

As for the isoamyl acetate, levels were high in GC, but yet again the sensory panel missed it.

Trial 3: actually consistent, lower esters by GC, no difference by sensory

Trial 4: also somewhat consistent...high ethyl hexoanoate, also found in the sensory.

I wonder if the sensory panel started to get biased, they did state the preferred the olive oil beer and could probably taste it. Also, it doesn't sound like they were doing triangle tasting tests, either.

Be that as it may, my point still stands that the study wasn't designed like it should...
 
remilard said:
I would hope that anybody criticizing the methods used to produce the paper in the OP would not seriously propose that a casual test with no trained tasting panel and statistical analysis is acceptable.
Click to expand...

No, it wouldn't be acceptable...just like it isn't acceptable to leave out a negative control.
 

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